Basicity Enhancement by Multiple Intramolecular Hydrogen Bonding in Organic Superbase N,N',N″,N‴-Tetrakis(3-(dimethylamino)propyl)triaminophosphazene
Related Experiment Video
Updated: Jan 4, 2026

Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
Sebastian Ullrich1, Danijela Barić2, Xiulan Xie1
1Fachbereich Chemie , Philipps-Universität Marburg , Hans-Meerwein-Straße , 35032 Marburg , Germany.
Abstract:
With the synthesis of N,N',N″,N‴-tetrakis(3-(dimethylamino)propyl)triaminophosphazene (TDMPP, 1), we present the first phosphazene superbase with enhanced basicity through the effect of multiple intramolecular hydrogen bonding (IHB). Due to intramolecular solvation of four NH protons, the proton affinity is even higher than that of second-order phosphazene (dma)P2-tBu. X-ray structural proof, NMR titration experiments, and computational investigations provide a more detailed quantitative description of the IHB influence on the superbasicity of 1 in solid-state, solution, and the gas-phase.
Related Concept Videos
Basicity of Heterocyclic Aromatic Amines
Basicity of Aliphatic Amines
To measure the basicity of amines, two conventions are generally used. The first defines Kb as the basicity constant for the deprotonation reaction of water by the amine, as presented in Figure 1. Conventionally, lower Kb indicates higher...
Basicity of Aromatic Amines
Acidity of 1-Alkynes
The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.
Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
Hydrogen Bonds

